Question: $ \left(\dfrac{5}{9} \div \dfrac{5}{4}\right) \div \dfrac{1}{9} = {?} $
Answer: Dividing by a fraction is the same as multiply by the reciprocal of that fraction. $ = \left(\dfrac{5}{9} \times \dfrac{4}{5}\right) \div \dfrac{1}{9} $ $ = \left(\dfrac{5 \times 4} {9 \times 5}\right) \div \dfrac{1}{9} $ $ = \dfrac{20}{45} \div \dfrac{1}{9} $ $ = \dfrac{20}{45} \times 9 $ $ = \dfrac{20 \times 9}{45 \times 1} $ $ = \dfrac{180}{45}$ Simplify: $ = 4$